Microtubules are major cytoskeletal structures responsible for maintaining genetic stability during cell division (Sammak and Borisy, 1987; McIntosh, 1994; Desai and Mitchinson, 1997). The dynamics of these polymers is absolutely crucial for this function that can be described as their growth rate at the plus ends, catastrophic shortening, frequency of transition between the two phases, pause between the two phases, their release from the microtubule organizing center and treadmilling (Margolis and Wilson, 1981; Mitchison and Kirschner, 1984; Kirschner and Mitchison, 1986; Margolis and Wilson, 1998; Jordan and Wilson, 2004). Microtubule lattice also serves as tracks for the axonal transport of organelles driven by anteriograde and retrograde molecular motors to generate and maintain axonal integrity (Joshi, 1998; Nogales, 2000). Interference with microtubule dynamics often leads to programmed cell death and thus microtubule-binding drugs are currently used to treat various malignancies in the clinic (Jordan and Wilson, 2004). Although useful, currently used microtubule drugs such as vincas and taxanes are limited due to the emergence of drug resistance. There have been multiple mechanisms for antimicrotubule drug resistance including overexpression of drug-efflux pumps, misexpression of tubulin isotypes, and perhaps mutational lesions in tubulin itself (Ranganathan et al., 1996; Giannakakou et al., 1997; Monzo et al., 1999; Dumontet et al., 2005).
The pharmacological profile of microtubule-binding agents, however, has not been ideal. Most of them need to be infused over long periods of time in the clinic because they are not water-soluble, and can cause hypersensitive reactions due to the vehicle solution (Rowinsky, 1997). Furthermore, normally dividing cells within the healthy tissues such as intestinal crypts, hair follicles, and the bone marrow are also vulnerable to these agents, leading to toxicities (Rowinsky, 1997). In addition, nerve cells dependent on molecular traffic over long distances undergo degenerative changes causing peripheral neuropathies (Pace et al., 1996; Crown and O'Leary, 2000; Theiss and Meller, 2000; Topp et al., 2000).
Noscapine ((S)-6,7-dimethoxy-3-((R)-4-methoxy-6-methyl-5,6,7,8-tetrahydro[1,3]-dioxolo-[4,5-g]isoquinolin-5-yl)isobenzo-furan-1(3H)-one), a safe antitussive agent for over 40 years, binds tubulin, arrests dividing cells in mitosis and induces apoptosis (Ye et al., 1998). It is well-tolerated in humans and has been shown to be non-toxic in healthy volunteers, including pregnant mothers (Dahlstrom et al., 1982; Karlsson et al., 1990; Jensen et al., 1992).
Unlike the other microtubule-targeting drugs, noscapine does not significantly change the microtubule polymer mass even at high concentrations. Instead, it suppresses microtubule dynamics by increasing the time that microtubules spend in an attenuated (pause) state when neither microtubule growth nor shortening is detectable (Landen et al., 2002). Thus, noscapine-induced suppression of microtubule dynamics, even though subtle, is sufficient to interfere with the proper attachment of chromosomes to kinetochore microtubules and to suppress the tension across paired kinetochores (Zhou et al., 2002a). This represents an improvement over the taxanes, the microtubule-bundling agents or overpolymerizers, and vincas, the depolymerizers, that cause toxicities in mitotic and post mitotic neurons at elevated doses. Noscapine thus effectively inhibits the progression of various cancer types both in cultured cells and in animal models with no obvious side effects (Ye et al., 1998; Landen et al., 2002; Zhou et al., 2002b; 2003; Landen et al., 2004). Surprisingly, the apoptosis is much more pronounced in cancer cells compared with normal healthy cells (Landen et al., 2002).
It would be desirable to have compounds, compositions and methods for preventing and/or treating various types of cancer, without significant associated side effects, that provide increased anti-cancer properties to that of noscapine. The present invention provides such compounds, compositions and methods.